This invention relates generally to methods and systems for balancing a rotatable member and, more particularly, to methods and systems of balancing a gas turbine engine rotor using a physical dimension to determine final balance.
At least some known rotatable members such as machine rotors include a monolithic rotor comprising only one piece. Other known rotors include separate portions that are assembled by coupling the portions together. Such rotors are generally balanced separately using a mock-up or dummy arbor that simulates each portion being assembled to its complementary portion. Any coupling eccentricity between the portion and the dummy arbor manifests itself as an unbalance of the assembly, resulting in vibration when the rotor is spinning. The unbalance due to the eccentricity is canceled during balancing of each of the portions. However, each portion may couple together differently during final assembly than it coupled to its respective dummy arbor during balancing, introducing an uncorrected eccentricity influence to the final assembly.